Implement for stabilizing cohesive and frictional earths to a considerable depth with binding agents

ABSTRACT

A drill rod and head combination including a radially extending cylindrical sleeve of particular construction and specially shaped helical flight beneath the sleeve, whereby when unscrewing the drill head from the ground and feeding a binding agent through the sleeve, the binding agent will be transported radially outwards into intimate admixture with the earth.

United States Patent [191 Granholm et al.

[451 Apr. 9, 1974 IMPLEMENT FOR STABILIZING COHESIVE AND FRICTIONAL EARTI-IS TO A CONSIDERABLE DEPTH WITH BINDING AGENTS [75] Inventors: Sven Axel Eden Granholm; Sven Torgny Thorsell, both of Skelleftea,

Sweden [73] Assignee: Linden-Alimak AB, Skelleftea,

Sweden [22] Filed: May 11, 1972 [21] Appl. No.: 252,234

[30] Foreign Application Priority Data May 11, 1971 Sweden 6105/71 [52] U.S. Cl 61/63, 175/324, 61/35 [51] Int. Cl E02d 3/00 [58] Field of Search 61/63; 259/9, 10; 175/324 [56] References Cited FOREIGN PATENTS OR APPLICATIONS 1,582,116 8/1969 France 61/63 283,301 5/1952 Switzerland 417/327 648,109 12/1950 Great Britain 417/327 Primary Examiner-Mervin Stein Assistant Examiner-Alex Grosz Attorney, Agent, or Firm-Fred Philpitt 5 7 ABSTRACT A drill rod and head combination including a radially extending cylindrical sleeve of particular construction and specially shaped helical flight beneath the sleeve, whereby when unscrewing the drill head from the ground and feeding a binding agent through the sleeve, the binding agent will be transported radially outwards into intimate admixture with the earth.

2 Claims, 3 Drawing Figures PATENIEDAPR 9 m4 (802,208 sum 3' 0F 3 Fig. 3

IMPLEMENT FOR STABILIZING COI-IESIVE AND FRICTIONAL EARTIIS TO A CONSIDERABLE DEPTH WITH BINDING AGENTS In French patent specification No. l 582 116 there is described a method of stabilizing cohesive and frictional earths to a considerable depth with binding agents, such as lime, cement, asphalt or tar products, by introducing into the ground to the desired depth a binding agent injection tool in the form of an earth drill provided at the lower end of the drill rod or shaft with a drill head having one or more helical flights and a number of outlet openings for the binding agent which is supplied through the drill rod.

The French patent specification No. l 582 116 also illustrates and describes a number of embodiments of an injection tool which are suitable for use in carrying out of the method. Thus, there is shown in FIGS. 16 to 19 an embodiment specially adapted for the supply of a powderous binding agent, for example unslaked lime, packed in capsules supplied through the tubular drill rod to a feed screw provided in the drill head and extending transversely to the drill rod, said screw tearing the capsule to pieces and transporting the liberated contents of the capsule laterally in both directions out through a plurality of comparatively small outlet openings provided in the wall of the cylindrical sleeve, in which the feed screw operates. The purpose of the said arrangement is to distribute the stabilizing agent evenly over the entire cross-sectional area of the column of earth material which is to be stabilized through mixing the binding agent therewith.

The present invention has for its object to eliminate certain inconveniences found in the injection tool illustrated in FIGS. [6 to 19 in the above-mentioned French patent specification. The several outlet openings in the long sleeve, in which the feed screw operates, are comparatively small and become readily blocked by pieces of the torn capsule wall or by binding agent which after taking up moisture from the surrounding ground has hardened, so that the implement becomes entirely inoperative or at any rate does not any longer guarantee the supply of the correct proportion of binding agent to the earth material during the withdrawing of the implement for the ground. According to the present invention the said inconveniences have been eliminated by making the feed screw single acting and by placing the same in a non-perforated cylindrical sleeve which extends radially outwardly in one direction only and is entirely open at its outer end so that the entire amount of binding agent is fed into the ground through the fully open end of the sleeve, the said end opening having so large a cross-sectional area that there will be no risk of the opening becoming clogged. The sleeve for the feed screw is given such a length that its outlet opening will be positioned close to the core or hub of the drill head, a number of helical flights positioned below the outlet opening being shaped in known manner with radial width evenly increasing from their upper end to their lower end, so that when unscrewing the injection tool from the ground with a forced axial feed movement which for each revolution of the earth drill is considerably smaller than the pitch of the helical flights, the stabilizing agent will be transported by the edge surfaces of the flights out towards the circumference of the drill head while being simultaneously mixed with the earth material.

The invention will now be descried more closely with reference to the accompanying drawings which as an example show a suitable embodiment of an injection earth drill.

FIG. 1 is a side view of the drill head and of the lower I portion of the drill rod.

FIG. 2 is an axial section through the drill head along a plane through the axis of the feed screw.

FIG. 3 shows a section through the drill head extending perpendicularly to the axis along the line III-III in FIG. 1.

On the drawing the reference numeral designates a drill head which by means of a suitable coupling 11 is detachably secured to the lower end of a tubular drill rod-12. The core or hub portion of the drill head 10 is formed by a tube 14 which has a considerably larger diameter than the drill rod 12 and is closed at its lower end by a chisel shaped drill point 15.

Onto the core tube 14 are secured by welding a lower group of two helical flights 16 and an upper group of two helical flights 17. The flights 16 in the lower group are each terminated at its lower end by a cutting edge 18 which is perpendicular to the axis of the drill head, and the flights 17 of the upper group are terminated at their upper ends each by a cutting edge 19 which also is perpendicular to the axis of the drill head. All cutting edges 18 and 19 are positioned in a common plane through the axis of the drill head. The radial width of each flight 16 and 17, respectively, decreases continuously from its cutting edge upwards, respectively, downwards, so that the edge surface 20 or 21 of each flight will follow an archimedian spiral.

Journalled in the hub tube 14 between the two groups of flights is a single-acting feed screw 22, the axis of which coincides with a plane through the cutting edges 18 and 19. The feed arrow 22 is rotatable in a sleeve 22 secured by welding to the hub tube 14 and open at its outer end only. At the opposite end of the feed screw is secured a conical gear wheel 24 which by means of a ball bearing 25 is joumalled in a short sleeve 26 which is secured by welding to the hub tube and the outer end of which is normally closed by a detachable lid 27. The conical gear wheel 24 cooperates with a conical wheel 28 on the lower end of a tubular driving shaft 29 telescopically passing through the tubular drill rod 12. The driving shaft 29 is joumalled at its lower end by means of a ball bearing 30 in a sleeve 31 which is inserted into the hub tube 14 from above and is detachably connected with the hub by means of two wedges 32 passing through diametrically positioned oblong holes in the hub tube 14 and in corresponding depressions in the insert sleeve 31. The latter sleeve is at its upper end shaped with coupling teeth 33 for cooperation with coupling teeth a coupling half, not

shown which is secured to the drill rod.

In the embodiment shown the feed screw projects through the hub a distance which substantially corresponds to the smallest width of the upper end lower flights. At its feed end the sleeve is cut off perpendicularly to its axis.

The reference numeral 34 designates capsules of plastic material, paper or the like, containing a powderous binding agent, for example unslaked lime. The capsules are supplied to the drill head in known manner through the hollow drive shaft 29.

The injection tool illustrated and described operates in the following manner.

After the tool, through rotation in a clockwise direction, has been screwed down into the ground to the desired depth, the direction of rotation of the drill rod 12 is reversed. Simultaneously there is enforced upon the drill rod an upwardly directed feed movement which for each revolution of the drill is considerably smaller than the pitch of the helical flights l6 and 17. Via the shaft 29 and the gears 24, 28 the feed screw is at the same time rotated with a suitable speed and there is supplied continuously through the hollow drive shaft capsules 34 containing the powdered binder. The capsules 34 are torn to pieces when they contact the feed screw, and the liberated powder binder is by means of the feed screw positively fed out through open end of the feed screw sleeve 23 and is delivered into the earth as a spiral-shaped string. During the continued pulling up of the implement, said string is contacted by the edge surfaces of the lower flights l6 and is transported by the said edge surfaces radially outwards to the desired distribution over the cross-sectional area of the earth column to be stabilized. At the same time the flights effectively mix the binding agent thus distributed over the cross-sectional area effectively with the earth material, so that the tool leaves behind itself a circular column consisting of an intimate mixture of earth material and binder powder. Said column has a comparatively large diameter, as a rule considerably exceeding half a meter, wherefore the positive distribution of the binding agent over closely positioned layers of earth material is a necessary condition for the obtaining of a sufficiently intimate admixture of the binding agent into the earth material.

The novel arrangement for the supply of powderous binding agent to the earth material around the drill head guarantees, through the absence of narrow outlet passages, that no passage will become clogged by hardened binding agent or by torn capsule walls. Should, on some occasion, the feed screw require to be cleaned, the feed screw 22 may be readily taken out through the tube 26 after the lid 27 has been removed.

in order to eliminate the risk of moisture penetrating from without into the feed screw and causing hardening of the binding agent present between the threads of the feed screw, the tube 23 may be cut off at its outlet end obliquely along a plane which is parallel with the drill axis, so that when unscrewing the tool the outlet opening will be directed opposite to the direction of rotation.

The tool according to the invention may be used to advantage also when it is desired to stabilize acolumn of earth material with a liquid stabilizing agent, for example a suspension of slaked lime in water.

What we claim is:

1. An improved drill rod and drill head combination device which is adapted to introduce binding agents into intimate admixture with the earth which is characterized by a. a drill head which has at least one helical flight disposed around its exterior surface, and having upper and lower cutting edges,

b. an elongated hollow drill tube having its lower end extending downwardly into the interior of the upper end of the drill head,

0. an unperforated cylindrical sleeve that extends between said upper and lower cutting edges radially outwardly from a point within the drill head to a point exterior of and in the rear vicinity of the exterior surface of the drill head,

(1. the inner end of said cylindrical sleeve having an opening which is closely adjacent to and aligned with the outlet end of said elongated hollow drill tube and the outer end of said cylindrical sleeve being completely open,

. a single acting feed screw disposed within said cylindrical sleeve with its outer end disposed closely adjacent to the outlet end of said cylindrical sleeve,

the inner end of said feed screw and the lower end of said hollow drill tube being operatively engaged in such a manner that rotation of said drill tube about a vertical axis will cause rotation of said feed screw about a horizontal axis,

g. the width of the part of the helical flight or flights disposed below said cylindrical sleeve increasing continuously from the upper end to the lower end so that the length of said lower cutting edge is substantially greater than the length of said cylindrical sleeve outside the drill head, whereby when unscrewing the drill head from the ground with an enforced axial movement, which for each revolution of the drill is considerably less than the pitch of the helical flights, and at the same time feeding the binding agent through said cylindrical sleeve, the binding agent will be transported radially outwards by the edge surfaces of said flights below said sleeve while being simultaneously mixed by the flights with the earth material.

2. A device according to claim 1, characterized in that the sleeve of the feed screw is cut out at its outlet end along a plane which is parallel with the axis of the earth drill so that when unscrewing the tool the outlet opening will become directed opposite to the direction of rotation. 

1. An improved drill rod and drill head combination device which is adapted to introduce binding agents into intimate admixture with the earth which is characterized by a. a drill head which has at least one helical flight disposed around its exterior surface, and having upper and lower cutting edges, b. an elongated hollow drill tube having its lower end extending downwardly into the interior of the upper end of the drill head, c. an unperforated cylindrical sleeve that extends between said upper and lower cutting edges radially outwardly from a point within the drill head to a point exterior of and in the rear vicinity of the exterior surface of the drill head, d. the inner end of said cylindrical sleeve having an opening which is closely adjacent to and aligned with the outlet end of said elongated hollow drill tube and the outer end of said cylindrical sleeve being completely open, e. a single acting feed screw disposed within said cylindrical sleeve with its outer end disposed closely adjacent to the outlet end of said cylindrical sleeve, f. the inner end of said feed screw and the lower end of said hollow drill tube being operatively engaged in such a manner that rotation of said drill tube about a vertical axis will cause rotation of said feed screw about a horizontal axis, g. the width of the part of the helical flight or flights disposed below said cylindrical sleeve increasing continuously from the upper end to the lower end so tHat the length of said lower cutting edge is substantially greater than the length of said cylindrical sleeve outside the drill head, whereby when unscrewing the drill head from the ground with an enforced axial movement, which for each revolution of the drill is considerably less than the pitch of the helical flights, and at the same time feeding the binding agent through said cylindrical sleeve, the binding agent will be transported radially outwards by the edge surfaces of said flights below said sleeve while being simultaneously mixed by the flights with the earth material.
 2. A device according to claim 1, characterized in that the sleeve of the feed screw is cut out at its outlet end along a plane which is parallel with the axis of the earth drill so that when unscrewing the tool the outlet opening will become directed opposite to the direction of rotation. 